Teleradiology – overview, systems and applications Dr Sanjoy Sanyal MBBS, MS, MSc (UK), ADPHA, ADHRD Seychelles Staff seminar on 27 July 2007 in Seychelles medical college

Dr Sanjoy Sanyal

MBBS, MS, MSc (UK), ADPHA, ADHRD

Seychelles

TABLE OF CONTENTS Definition / types of teleradiology Components Configurations Equipment specifications DICOM PACS Applications Telemammography Costs References

Definition / types of teleradiology

Components

Configurations

Equipment specifications

DICOM

PACS

Applications

Telemammography

Costs

References

1. DEFINITION Teleradiology: A means of electronically transmitting patient’s radiographic images and consultative text from one location to another

1. TYPES OF TELEMEDICINE

2. COMPONENTS – Telemedicine system in general

2. COMPONENTS – Basic teleradiology system Image sending station Transmission network Receiving/image review station

Image sending station

Transmission network

Receiving/image review station

A. Image Sending Station Image (film) digitizer Network interface device (e.g. phone modem)

Image (film) digitizer

Network interface device (e.g. phone modem)

Image (film) digitizer Direct digitization : No need for X-ray film and processing equipment (best) TV camera digitizers (‘low-end’) CCD scanner digitizers (‘mid-level’) Laser scanner digitizers (‘high-end’) Last three digitizers perform same function: Input X-ray film -> into scanner; analog image of film -> digital image.

Direct digitization : No need for X-ray film and processing equipment (best)

TV camera digitizers (‘low-end’)

CCD scanner digitizers (‘mid-level’)

Laser scanner digitizers (‘high-end’)

Last three digitizers perform same function: Input X-ray film -> into scanner; analog image of film -> digital image.

Camera digitizer

Network interface device Film digitizer has converted the image to digital format Data is sent to the modem upon command of the equipment operator Modem converts digital data into electrical impulses that are sent along transmission network.

Film digitizer has converted the image to digital format

Data is sent to the modem upon command of the equipment operator

Modem converts digital data into electrical impulses that are sent along transmission network.

B. Transmission Network Wire Fiberoptics Microwave Provided by telephone companies. This network utilizes both wire and fiberoptics Transmission speed (and cost) closely related to transmission mode.

Wire

Fiberoptics

Microwave

Provided by telephone companies. This network utilizes both wire and fiberoptics

Transmission speed (and cost) closely related to transmission mode.

C. Receiving / Image Reviewing Station 1. Network interface (modem) 2. PC with storage medium (e.g. disc drive) 3. One or two TV monitors 4. Optional hard copy device printer

1. Network interface (modem)

2. PC with storage medium (e.g. disc drive)

3. One or two TV monitors

4. Optional hard copy device printer

Receiving/Image Review Station

3. CONNECTION CONFIGURATIONS Point-to-point connection Local Area Network (LAN) Wide Area Network (WAN)

Point-to-point connection

Local Area Network (LAN)

Wide Area Network (WAN)

A. Point-to-point connection The basic sending and review station directly connected by a dedicated transmission network (e.g. a single wire or fiberoptic cable)

The basic sending and review station directly connected by a dedicated transmission network (e.g. a single wire or fiberoptic cable)

A. Point-to-point connection

A. Point-to-point connection

B. Local Area Network (LAN) Dedicated transmission network Multiple sending / review stations attached Images can be sent from several different locations within a building (or cluster of buildings) to a review station

Dedicated transmission network

Multiple sending / review stations attached

Images can be sent from several different locations within a building (or cluster of buildings) to a review station

B. Local Area Network (LAN)

C. Wide Area Network (WAN) Many LANs interconnected - ‘super’ network Connected by routers Interconnected LANs represented as ‘ network cloud ’

Many LANs interconnected - ‘super’ network

Connected by routers

Interconnected LANs represented as ‘ network cloud ’

C. Wide Area Network (WAN)

C. WAN – Telephone network Telephone network services can be thought of as a WAN Widely used transmission network Advantages of using the telephone network (1) It already exists (2) Inner workings / complexities of network are transparent to end users (3) Allows for readily available long / short distance connections (4) Costs are low

Telephone network services can be thought of as a WAN

Widely used transmission network

Advantages of using the telephone network

(1) It already exists

(2) Inner workings / complexities of network are transparent to end users

(3) Allows for readily available long / short distance connections

(4) Costs are low

Server-mediated communication

Server-mediated communication

4. EQUIPMENT SPECIFICATIONS A. Sending Station Specifications Image resolution Image compression Transmission speed

A. Sending Station Specifications

Image resolution

Image compression

Transmission speed

Image resolution Pixel : 512 x 512 (w x h), 1024 x 1024, or 2048 or 2048 Grey scale (density) number : 256 (8-bit depth) to 4096 (12 bit-depth) File size: 512 x 512 x 8 bit-depth = 2,097,152 bits 1024 x 1024 x 12 bit-depth = 12,582,912 bits (6 times larger file size)

Pixel : 512 x 512 (w x h), 1024 x 1024, or 2048 or 2048

Grey scale (density) number : 256 (8-bit depth) to 4096 (12 bit-depth)

File size:

512 x 512 x 8 bit-depth = 2,097,152 bits

1024 x 1024 x 12 bit-depth = 12,582,912 bits (6 times larger file size)

Image resolution – pixels 240 dpi 120 dpi 60 dpi 30 dpi

Image resolution – grey scale 255 grey levels / pixel 15 grey levels / pixel 5 grey levels / pixel 2 grey levels / pixel

Image compression Compression algorithms: DCT Lossy: JPEG (common) Lossless: Huffman JPG; JPG-LS; RLE Compression ratios: 2:1 to > 15:1 < 3:1 is lossless > 3:1 is lossy

Compression algorithms: DCT

Lossy: JPEG (common)

Lossless: Huffman JPG; JPG-LS; RLE

Compression ratios: 2:1 to > 15:1

< 3:1 is lossless

> 3:1 is lossy

Image compression

Image compression

Image compression

Transmission DS 0 (64 Kbps) ISDN (128 Kbps) T 1 (1.544 Mbps) ATM: Asynchronous Transfer Mode

DS 0 (64 Kbps)

ISDN (128 Kbps)

T 1 (1.544 Mbps)

ATM: Asynchronous Transfer Mode

Transmission speed Balance resolution, compression, and transmission speed parameters

Balance resolution, compression, and transmission speed parameters

Transmission speed

4. EQUIPMENT SPECIFICATIONS B. Receiving/Image Review Station specifications Modem : receiving unit modem must be > maximum speed of sending station Computer hardware Image enhancement software TV monitor : Resolution, size, split-screen, brightness

B. Receiving/Image Review Station specifications

Modem : receiving unit modem must be > maximum speed of sending station

Computer hardware

Image enhancement software

TV monitor : Resolution, size, split-screen, brightness

Image enhancement software Grey scale window/level Magnification image enhancement Colour, grey-scale mapping Positive-negative reversal Annotation Minification Edge enhancement Image flip/rotate Cine and histogram equalization

Grey scale window/level

Magnification image enhancement

Colour, grey-scale mapping

Positive-negative reversal

Annotation

Minification

Edge enhancement

Image flip/rotate

Cine and histogram equalization

TV monitor Resolution : 512 x 512 pixels to 2048 x 2048 pixels Size : 14 – 21 inches Split-screen : Display 2 or more different images at the same time Brightness : High footlamberts (greater brightness) better Brightness differential between shades is greater Easier for the human eye to detect

Resolution : 512 x 512 pixels to 2048 x 2048 pixels

Size : 14 – 21 inches

Split-screen : Display 2 or more different images at the same time

Brightness :

High footlamberts (greater brightness) better

Brightness differential between shades is greater

Easier for the human eye to detect

Digital display monitors Digital display monitors : For decoding digital images for producing diagnostic quality images for reporting Quality concerns : Whether they can match image resolution of X-ray film Pixel content: Lack of resolution is not because of the pixel content; typically 2K pixels x 2K lines Level of contrast : The problem is with the level of contrast - usually <100 shades of grayscale

Digital display monitors : For decoding digital images for producing diagnostic quality images for reporting

Quality concerns : Whether they can match image resolution of X-ray film

Pixel content: Lack of resolution is not because of the pixel content; typically 2K pixels x 2K lines

Level of contrast : The problem is with the level of contrast - usually <100 shades of grayscale

Digital display monitors Special techniques for correcting deficiency: Histogram-based image transformation Filter-based image transformation Unsharp mask These techniques give radiologist the ability to use ‘window’ and ‘level’ control (sort of contrast and brightness adjustments) to get adequate contrast distinction for confident reporting

Special techniques for correcting deficiency:

Histogram-based image transformation

Filter-based image transformation

Unsharp mask

These techniques give radiologist the ability to use ‘window’ and ‘level’ control (sort of contrast and brightness adjustments) to get adequate contrast distinction for confident reporting

Contrast-brightness control

Digital display monitor

5. DICOM DICOM : Digital imaging & communication ACR / NEMA standard: A set of rules Medical scanners (US, CT, MRI, X-ray) store and exchange images in DICOM format.

DICOM : Digital imaging & communication

ACR / NEMA standard: A set of rules

Medical scanners (US, CT, MRI, X-ray) store and exchange images in DICOM format.

5. DICOM Allows exchange of images between digital imaging machines, computers and hospitals. Allows teleradiology to expand from a vendor-dependent proprietary protocols and hardware to an open Internet-like system

Allows exchange of images between digital imaging machines, computers and hospitals.

Allows teleradiology to expand from a vendor-dependent proprietary protocols and hardware to an open Internet-like system

DICOM images

DICOM viewer

6. PACS PACS: Picture Archiving and Communication System For distribution , storage and management of digital images and patient information. Aiming towards filmless hospital Web-based PACS (AMICAS ® Inc): D iagnostic-quality radiology image management services; secure image capture, distribution, workflow integration and image archiving.

PACS: Picture Archiving and Communication System

For distribution , storage and management of digital images and patient information.

Aiming towards filmless hospital

Web-based PACS (AMICAS ® Inc): D iagnostic-quality radiology image management services; secure image capture, distribution, workflow integration and image archiving.

PACS network

7. APPLICATIONS Radiologists on call Hospital physicians Primary care / rural physicians Tertiary subspecialty consultations Computer-aided diagnosis (CAD)

Radiologists on call

Hospital physicians

Primary care / rural physicians

Tertiary subspecialty consultations

Computer-aided diagnosis (CAD)

A. Radiologists on call On-call radiologist uses portable telerad receiving station at home Patient images transmitted from radiology dept to radiologist’s home for immediate review

On-call radiologist uses portable telerad receiving station at home

Patient images transmitted from radiology dept to radiologist’s home for immediate review

B. Hospital physicians ICU patient images taken in Radiology Department Quickly transmitted to ICU for review by the team responsible for that patient's care Other involved physicians can also view images

ICU patient images taken in Radiology Department

Quickly transmitted to ICU for review by the team responsible for that patient's care

Other involved physicians can also view images

C. Primary care / rural physicians Primary physician can send images taken in the clinic to a radiologist in a distant location for reading and consultation

Primary physician can send images taken in the clinic to a radiologist in a distant location for reading and consultation

C. Primary / rural physicians

D. Tertiary super-specialist radiology consultations A community hospital radiologist can send a complete set of images to a tertiary super-specialist (i.e. paediatric radiologist)

A community hospital radiologist can send a complete set of images to a tertiary super-specialist (i.e. paediatric radiologist)

E. Computer-aided diagnosis Processing / analyzing digital medical images on workstation allows computer assistance to physician for interpretation Drawback : Increases number of negative / unnecessary biopsies without increasing incidence of positive diagnosis in mammography

Processing / analyzing digital medical images on workstation allows computer assistance to physician for interpretation

Drawback : Increases number of negative / unnecessary biopsies without increasing incidence of positive diagnosis in mammography

E. Computer-aided diagnosis

E. Computer-aided diagnosis

7. TELEMAMMOGRAPHY More women in remote areas Mammography experts are in cities Mammograms require special expertise Mammogram films are 35-55 MB/film WHY?

More women in remote areas

Mammography experts are in cities

Mammograms require special expertise

Mammogram films are 35-55 MB/film

7. TELEMAMMOGRAPHY High resolution is must for minute lesions So cannot compress images So need high-speed transmission lines Satellite and T1 is the answer NASA is the satellite and telemedicine expert

High resolution is must for minute lesions

So cannot compress images

So need high-speed transmission lines

Satellite and T1 is the answer

NASA is the satellite and telemedicine expert

7. TELEMAMMOGRAPHY STN: Satellite Telemammography Network Ka-Band satellites: Advanced Communication Technology Satellite (ACTS) Earth stations: T1 VSAT (Very Small Aperture Terminal) #1: Cleveland Clinic, OH #2: NASA Glenn Research Center @Lewis Field – ASCL #3: University of Virginia, Charlottesville

STN: Satellite Telemammography Network

Ka-Band satellites: Advanced Communication Technology Satellite (ACTS)

Earth stations: T1 VSAT (Very Small Aperture Terminal)

#1: Cleveland Clinic, OH

#2: NASA Glenn Research Center @Lewis Field – ASCL

#3: University of Virginia, Charlottesville

Satellite network

NASA satellite

Earth station – NASA Glenn

Earth station – University

Radiology - reading films

9. COSTS Low end equipment: $15,000 to $20,000 High performance systems: > $100,000 High quality sending station: ~ $35,000 to $40,000 Dual CRT receiving / viewing station: $45,000 to $55,000 ( Figures are as of 1 st half of this decade )

Low end equipment: $15,000 to $20,000

High performance systems: > $100,000

High quality sending station: ~ $35,000 to $40,000

Dual CRT receiving / viewing station: $45,000 to $55,000

( Figures are as of 1 st half of this decade )

10. REFERENCES University of Iowa: http://www.radiology.uiowa.edu/MoreRAD/Teleradiology/Tele.html Stephen Kinnear: http://www.scit.wlv.ac.uk/~c9581158/graphic/graphic.html Sreedhar Raja: http://www.websamba.com/dicom4india Chris Rorden: http://www.psychology.nottingham.ac.uk/staff/cr1/dicom.html#contrast

University of Iowa: http://www.radiology.uiowa.edu/MoreRAD/Teleradiology/Tele.html

Stephen Kinnear: http://www.scit.wlv.ac.uk/~c9581158/graphic/graphic.html

Sreedhar Raja: http://www.websamba.com/dicom4india

Chris Rorden: http://www.psychology.nottingham.ac.uk/staff/cr1/dicom.html#contrast

10. REFERENCES NHS Purchasing and Supply Agency, UK http:// www.pasa.doh.gov.uk/dme/radiology/pacs.stm Osman Ratib: http://www.hon.ch/Library/papers/ratib.html NASA Glen Research Center: http://web.archive.org/web/20051002003701/ctd.lerc.nasa.gov/5610/mammography/SLSandE.html http://www.nasa.gov/centers/glenn/news/pressrel/97_telem.html

NHS Purchasing and Supply Agency, UK http:// www.pasa.doh.gov.uk/dme/radiology/pacs.stm

Osman Ratib: http://www.hon.ch/Library/papers/ratib.html

NASA Glen Research Center: http://web.archive.org/web/20051002003701/ctd.lerc.nasa.gov/5610/mammography/SLSandE.html

http://www.nasa.gov/centers/glenn/news/pressrel/97_telem.html

10. REFERENCES NASA Glen Research Center: http://www.grc.nasa.gov/WWW/RT1995/5000/5660k2.htm SNAB: http://ctd.grc.nasa.gov/organization/branches/snab/telemedicine.html http://www.medicalimagingmag.com/issues/articles/2006-12_07.asp Wootton and Craig. Introduction to Telemedicine. 1999.

NASA Glen Research Center: http://www.grc.nasa.gov/WWW/RT1995/5000/5660k2.htm

SNAB: http://ctd.grc.nasa.gov/organization/branches/snab/telemedicine.html

http://www.medicalimagingmag.com/issues/articles/2006-12_07.asp

Wootton and Craig. Introduction to Telemedicine. 1999.